jury-rig broken sign mechanism

Should improve situation on #811

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncrypt.java

@@ -68,6 +68,7 @@ public class PgpSignEncrypt {
     private String mSymmetricPassphrase;
     private int mSymmetricEncryptionAlgorithm;
     private long mSignatureMasterKeyId;
+    private Long mSignatureSubKeyId;
     private int mSignatureHashAlgorithm;
     private String mSignaturePassphrase;
     private long mAdditionalEncryptId;
@@ -101,6 +102,7 @@ public class PgpSignEncrypt {
         this.mSymmetricPassphrase = builder.mSymmetricPassphrase;
         this.mSymmetricEncryptionAlgorithm = builder.mSymmetricEncryptionAlgorithm;
         this.mSignatureMasterKeyId = builder.mSignatureMasterKeyId;
+        this.mSignatureSubKeyId = builder.mSignatureSubKeyId;
         this.mSignatureHashAlgorithm = builder.mSignatureHashAlgorithm;
         this.mSignaturePassphrase = builder.mSignaturePassphrase;
         this.mAdditionalEncryptId = builder.mAdditionalEncryptId;
@@ -125,6 +127,7 @@ public class PgpSignEncrypt {
         private String mSymmetricPassphrase = null;
         private int mSymmetricEncryptionAlgorithm = 0;
         private long mSignatureMasterKeyId = Constants.key.none;
+        private Long mSignatureSubKeyId = null;
         private int mSignatureHashAlgorithm = 0;
         private String mSignaturePassphrase = null;
         private long mAdditionalEncryptId = Constants.key.none;
@@ -179,6 +182,11 @@ public class PgpSignEncrypt {
             return this;
         }
 
+        public Builder setSignatureSubKeyId(long signatureSubKeyId) {
+            mSignatureSubKeyId = signatureSubKeyId;
+            return this;
+        }
+
         public Builder setSignatureHashAlgorithm(int signatureHashAlgorithm) {
             mSignatureHashAlgorithm = signatureHashAlgorithm;
             return this;
@@ -309,20 +317,26 @@ public class PgpSignEncrypt {
         /* Get keys for signature generation for later usage */
         CanonicalizedSecretKey signingKey = null;
         if (enableSignature) {
-            CanonicalizedSecretKeyRing signingKeyRing;
+
+            // If we weren't handed a passphrase, throw early
+            if (mSignaturePassphrase == null) {
+                throw new NoPassphraseException();
+            }
+
             try {
-                signingKeyRing = mProviderHelper.getCanonicalizedSecretKeyRing(mSignatureMasterKeyId);
+                // fetch the indicated master key id (the one whose name we sign in)
+                CanonicalizedSecretKeyRing signingKeyRing =
+                        mProviderHelper.getCanonicalizedSecretKeyRing(mSignatureMasterKeyId);
+                // fetch the specific subkey to sign with, or just use the master key if none specified
+                long signKeyId = mSignatureSubKeyId != null ? mSignatureSubKeyId : mSignatureMasterKeyId;
+                signingKey = signingKeyRing.getSecretKey(signKeyId);
+                // make sure it's a signing key alright!
             } catch (ProviderHelper.NotFoundException e) {
                 throw new NoSigningKeyException();
             }
-            try {
-                signingKey = signingKeyRing.getSigningSubKey();
-            } catch (PgpGeneralException e) {
-                throw new NoSigningKeyException();
-            }
 
-            if (mSignaturePassphrase == null) {
-                throw new NoPassphraseException();
+            if ( ! signingKey.canSign()) {
+                throw new NoSigningKeyException();
             }
 
             updateProgress(R.string.progress_extracting_signature_key, 0, 100);

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainIntentService.java

@@ -50,6 +50,7 @@ import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.UncachedKeyRing;
 import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
 import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralMsgIdException;
+import org.sufficientlysecure.keychain.provider.CachedPublicKeyRing;
 import org.sufficientlysecure.keychain.provider.KeychainContract.KeyRingData;
 import org.sufficientlysecure.keychain.provider.KeychainContract.KeyRings;
 import org.sufficientlysecure.keychain.provider.KeychainDatabase;
@@ -128,7 +129,7 @@ public class KeychainIntentService extends IntentService implements Progressable
     public static final String SELECTED_URI = "selected_uri";
 
     // encrypt
-    public static final String ENCRYPT_SIGNATURE_KEY_ID = "secret_key_id";
+    public static final String ENCRYPT_SIGNATURE_MASTER_ID = "secret_key_id";
     public static final String ENCRYPT_USE_ASCII_ARMOR = "use_ascii_armor";
     public static final String ENCRYPT_ENCRYPTION_KEYS_IDS = "encryption_keys_ids";
     public static final String ENCRYPT_COMPRESSION_ID = "compression_id";
@@ -251,7 +252,7 @@ public class KeychainIntentService extends IntentService implements Progressable
                 int source = data.get(SOURCE) != null ? data.getInt(SOURCE) : data.getInt(TARGET);
                 Bundle resultData = new Bundle();
 
-                long signatureKeyId = data.getLong(ENCRYPT_SIGNATURE_KEY_ID);
+                long sigMasterKeyId = data.getLong(ENCRYPT_SIGNATURE_MASTER_ID);
                 String symmetricPassphrase = data.getString(ENCRYPT_SYMMETRIC_PASSPHRASE);
 
                 boolean useAsciiArmor = data.getBoolean(ENCRYPT_USE_ASCII_ARMOR);
@@ -280,14 +281,20 @@ public class KeychainIntentService extends IntentService implements Progressable
                             .setOriginalFilename(originalFilename);
 
                     try {
-                        builder.setSignatureMasterKeyId(signatureKeyId)
-                                .setSignaturePassphrase(
-                                        PassphraseCacheService.getCachedPassphrase(this, signatureKeyId))
+                        CachedPublicKeyRing signingRing =
+                                new ProviderHelper(this).getCachedPublicKeyRing(sigMasterKeyId);
+                        long sigSubKeyId = signingRing.getSignId();
+                        // It is assumed that the passphrase was cached prior to the service call.
+                        String passphrase = PassphraseCacheService.getCachedPassphrase(this, sigSubKeyId);
+                        builder.setSignatureMasterKeyId(sigMasterKeyId)
+                                .setSignatureSubKeyId(sigSubKeyId)
+                                .setSignaturePassphrase(passphrase)
                                 .setSignatureHashAlgorithm(
                                         Preferences.getPreferences(this).getDefaultHashAlgorithm())
-                                .setAdditionalEncryptId(signatureKeyId);
-                    } catch (PassphraseCacheService.KeyNotFoundException e) {
+                                .setAdditionalEncryptId(sigMasterKeyId);
+                    } catch (PgpGeneralException e) {
                         // encrypt-only
+                        // TODO Just silently drop the requested signature? Shouldn't we throw here?
                     }
 
                     // this assumes that the bytes are cleartext (valid for current implementation!)

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptFileActivity.java

@@ -252,7 +252,7 @@ public class EncryptFileActivity extends DrawerActivity implements EncryptActivi
             }
             data.putString(KeychainIntentService.ENCRYPT_SYMMETRIC_PASSPHRASE, passphrase);
         } else {
-            data.putLong(KeychainIntentService.ENCRYPT_SIGNATURE_KEY_ID, mSigningKeyId);
+            data.putLong(KeychainIntentService.ENCRYPT_SIGNATURE_MASTER_ID, mSigningKeyId);
             data.putLongArray(KeychainIntentService.ENCRYPT_ENCRYPTION_KEYS_IDS, mEncryptionKeyIds);
         }
         return data;

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptTextActivity.java

@@ -36,6 +36,9 @@ import org.sufficientlysecure.keychain.compatibility.ClipboardReflection;
 import org.sufficientlysecure.keychain.helper.Preferences;
 import org.sufficientlysecure.keychain.helper.ShareHelper;
 import org.sufficientlysecure.keychain.pgp.KeyRing;
+import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
+import org.sufficientlysecure.keychain.provider.CachedPublicKeyRing;
+import org.sufficientlysecure.keychain.provider.ProviderHelper;
 import org.sufficientlysecure.keychain.service.KeychainIntentService;
 import org.sufficientlysecure.keychain.service.KeychainIntentServiceHandler;
 import org.sufficientlysecure.keychain.service.PassphraseCacheService;
@@ -235,7 +238,7 @@ public class EncryptTextActivity extends DrawerActivity implements EncryptActivi
             }
             data.putString(KeychainIntentService.ENCRYPT_SYMMETRIC_PASSPHRASE, passphrase);
         } else {
-            data.putLong(KeychainIntentService.ENCRYPT_SIGNATURE_KEY_ID, mSigningKeyId);
+            data.putLong(KeychainIntentService.ENCRYPT_SIGNATURE_MASTER_ID, mSigningKeyId);
             data.putLongArray(KeychainIntentService.ENCRYPT_ENCRYPTION_KEYS_IDS, mEncryptionKeyIds);
         }
         return data;
@@ -310,8 +313,12 @@ public class EncryptTextActivity extends DrawerActivity implements EncryptActivi
             }
 
             try {
-                if (mSigningKeyId != 0 && PassphraseCacheService.getCachedPassphrase(this, mSigningKeyId) == null) {
-                    PassphraseDialogFragment.show(this, mSigningKeyId,
+                if (mSigningKeyId != 0) {
+                    CachedPublicKeyRing signingRing =
+                            new ProviderHelper(this).getCachedPublicKeyRing(mSigningKeyId);
+                    long sigSubKeyId = signingRing.getSignId();
+                    if (PassphraseCacheService.getCachedPassphrase(this, sigSubKeyId) == null) {
+                        PassphraseDialogFragment.show(this, sigSubKeyId,
                                 new Handler() {
                                     @Override
                                     public void handleMessage(Message message) {
@@ -325,6 +332,9 @@ public class EncryptTextActivity extends DrawerActivity implements EncryptActivi
 
                         return false;
                     }
+                }
+            } catch (PgpGeneralException e) {
+                Log.e(Constants.TAG, "Key not found!", e);
             } catch (PassphraseCacheService.KeyNotFoundException e) {
                 Log.e(Constants.TAG, "Key not found!", e);
             }